Railway traffic controlling apparatus



Aug. 17, 1943. H s. YOUNG RAILWAY TRAFFIC CONTROLLING APPARATUS Filed sept. 27, 1941 4 Sheets-Sheet l NNN 1ML il w :NvENToR Henry 05mg.

[IIS AT'TORNEY Aug. 17, 1943. H, s. YOUNG RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Sept. 27, 1941 4 SheetS-Shee 2 HIS' A'TORNEY Aug. 17, 1943. H. s. YOUNG RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Sept. 27, 1941 4 Sheets-Sheet 3 WJ n ma m v .m m M wd S @m m W www Aug. 17, 1943. H. s. YOUNG 2,326,991

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Sept. 27, 1941 4 Sheets-Sheet 4 HIS AroRNEY NBNQNWQN QIJILJV my Ww y HW kwmwmlsd -Iif Irl -1%. -1 1 rw@ -mm .j Nw u www 1% I @N w SNR, @LNAH WW m wm @V @www T U w c m v .m o b im w Y S* w @www u w m www@ Il D L c f NEN 1 .w b nu Vgm www EN mwmkqr@ b Il: b L wh b www n .n SNN m Mmm du b IVW@ vm maval Patented Aug. 17, 1943 RAILWAY TRAFFIC CONTROLLING APPARATUS Henry S. Young, Wilkinsburg, Pa., assigner to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application September 27, 15.41, Serial No. 41,2%,627

(Cl. 24S- Jil "2z claims.

My invention Yrelates to railway trailic controlling apparatus for governing the movement of traffic over stretchesrof single track over which traffic moves in both directions, and in its specific embodiment, to the provision of an improved -absolute permissive block signaling system in which the signals for both directions are controlled' over circuits employing but two line wires which may be. energized at one end or the other by current of normal or reverse polarity to provide three position control of the sighals, and in Which the. direction of trac is manually governed from a central point by 'means of a Ycentralized traflic control system.

One feature of my invention is the provision 'of an improved system of directional control for 'systems of this characten'which functions automatically when a train enters an unoccupied single track stretch from either end, to estabvlish the corresponding k.traiiic ldirection `.or to maintain it if already established, to thereby effect the clearing of the intermediate. signals for the corresponding direction located Within the stretch and ahead of'l the train, the purpose v being to avoid delays to trafc in the event of failure of the centralized traffic control system by means of which the direction of traflic is es-` tablished in normal operation.

Another feature of my invention is the provision of a single track signaling system of relatively low cost in which hand throw switches may be used in lieu of the usual power operated track switches and-in the provision of an improved system of time-locking for the signals for a system of this character, for the purpose lof preventing a change in the established route under unsafe trafiic conditions. Y

My invention also includes the provision of novel arrangements'for thercontrol of a block indicator for visually indicating at the control cnice when a train moving ink either direction occupies any portion of the single track stretch,

and forrinterlocking the circuits controlled by the control levers for the opposing head'block signalsv governing traiiic movements into the single track stretch so as tc prevent interference with trainmovements in the event of improper manipulation of these levers. f

I shall describe one form of apparatus embodying my invention and one modication thereofv and shall then point out the novel features Vthereof in claims. Y A

Referring to the accompanying drawings, Figs. 1A, 1B4 and 1C, when placed end/to end in that order with Fig. 1A at the left, constitute a,

diagrammatic view showing trackway apparatus embodying one form of my invention applied to the portion of a single tra-ck railroad located between and including the ends of two adjacent passing sidings. Fig. 2 shows the control oice apparatus including the signal control levers together with an illuminated track diagram-oi the stretch of track and associated apparatus forV effecting the control and supervision of train movements over the single track block of Figs. 1A, 1B and 1C. Fig. 3 illustrates a modification of the circuits of Fig. 1A for controlling the block indicator,

Similar reference characters refer to similar parts in each of the views.

In order to simplify the drawings and to enable the circuits to be more readily traced, I

have herein identified each switch and signal by a numberand each relay by a letter or combination of letters with a numerical prefix identifying the switch or signal with which the relay is associated. Insteal of showing the sources of current for energizing the various circuits, I have shown only the terminals ofthe sources, these beingidentied by the references Band C; referring to the power supply or positive 'and the common return or negative terminals respectively. Y

The track diagram extending across the top of each of the views Figs,V 1A, 1B andlC represents a stretch of railway track constituting a typical single track block to which my invention is applied in themanner illustrated bythe 'cir-A, cuits below theldiagram. This stretch of track is provided with continuous track circuits, being divided into track sections T by the usual insulated joints, and each section T is provided with a track circuit having a current source connected across the track rails'at yone endand a track relay TR connected across the track rails at its opposite end.

The hand-throw switches ISW and SSW, when reversed, connect the ends of the single track stretch with a non-track-circuited passing siding PS, and when normal, as shown, with a stretch of main track MT. i

The trackvswitches ISW and 3SW are located in the usual detector track section having thetrack relays ITR. and 3TR over which trafc movements are governed by the signals bearing the references 2 and 4 respectively, each signal being identified by a distinguishing suflix. The single track block to which my invention is applied extends from the head block signal 2BA 0r ZRB through track sections IT, IUT to 15T,

inclusive, and 3T to the opposing head block signal ILA or 4LB. The spacing of trains moving in the same direction through the block is governed by the intermediate signals I2 and I4, or by signals I3 and I5 of Fig. 1B, as will be readily understood.

The territory illustrated may be extended through the passing siding to the Yentrance to an adjacent, single track block, merely by placing Fig. 1A at the right of Fig. 1C. When so arranged, Figs. 1C and 1A illustrate a block extending from signal 4RA or 4KB through track sections 3T, MT and IT to an opposing signal such as signal ZLA or ZLB but located in the next single track block to the right of that described above, but since the circuits for controlling these signals 4R and 2L form no part of the present invention they have not been shown herein, suitable circuits being well known. For example, these signals may be controlled by circuits similar to those for signals R2 and L4 shown in my Patent No. 2,282,841, granted May 12, 1942, for Railway trame Vcontrolling apparatus.

It will be understood that each of the head block signals is controlled automatically by the track relays in accordance with tramo conditions in advance, and is also subject to manual control from the central oice illustrated in Fig. 2, through the medium of a centralized traillc control system.

The communication system connecting the oice with the various iield locations may be of any suitable type, and as shown herein it is to be understood to be of the impulse code type such as that shown in letters Patent of the United States No. 2,229,249, granted January 21, 1941, to Lloyd V. Lewis, for Remote control systems. In this systemy communication is established intermittently between the control ofiice and various field stations over a single pair of line wires Y and Z which, it is to be understood, extend from the oillce (assumed to be at the left cf the controlled territory) through each station corresponding to the location of a head block signal such as those shown in Figs. 1A and 1C iri the manner illustrated in Fig. 10 of the Lewis patent.

Referring to Fig. 1A, for example, the dotand-dash line rectangle bearing the legend CTC station unitY No. 2 represents the station coding unit illustrated in Figs. 6 and '7 of this patent by means of which the central oice operator governs' the signal control relays 2LHS, iRHS and 2US corresponding to the similarly designated relays in Fig. 8 of the patent, while the dot-and-dasli line rectangle in Fig. 3 represents a similar unit at anoth'r location, and those in Fig. 2 represent the corresponding opfce coding and storage units such as are shown in Figs. 1 to 5 of the patent. The station unit terminals bear numerical designations 21, 84 to 92 and in Fig. 1A and likewise in Fig. 1C, which are the same as those of the corresponding terminals of the station unit as shown inV Figs. 7 and 8 of the patent. Certain of these represent channels for communication, by code, with the corresponding storage unit at the cnice, and in order that the cnice terminals of the circuits controlled cver these channels may be rmdlly identified without the necessity of tracing the code operation in detail, they have been given similar numercial designations in Fig` 2 herein. For example, the transmission of a control code including the code call for station No.

2 with signal control lever 2 of Fig. 2 in its righthand position causes the selector relay 2S to be picked up thereby energizing wire to pick up the stick relay ZRHS, Fig. 1A, which relay then remains picked up until a control code is transmitted to station No. 2 with lever 2 in its center or left-hand position, whereupon relay ZRHS is released, as explained in the patent. The transmission of indications is carried out in an analogous manner; when a. train enters section IT for example, the track relay I'IR releases, deenergizing its repeater relay ITZ which releases to energize wire 9i, causing the transmission of an indication code to effect the energl'zation of the track indication stick relay ITK (corresponding to relay IIK of Fig. 5 of the patent), and when relay ITZ again picks up, a second code is transmitted to cause relay ITK to release, relay ITK controlling the "OS" lamp ITE, which is lighted to indicate the occupancy of the corresponding switch section of the miniature track diagram at the ofce. Each station unit also controls, over the channel corresponding to Wire 89, a block indicator lamp 2-4BE in the track diagram, which lamp is lighted when any portion of the single track block is occupied, and the indication relays 2RBK and v4LBK which control the block indicator lamp also control the energization of a polar stick relay 2-4LP by means of which the circuits controlled by the signal levers 2 and 4 are interlocked as hereinafter described, so as to prevent interference with the established traillc direction by operation of these levers except under proper conditions. The indication stick relays LHK, NK and RHK which govern the signal indication lamps associated with levers 2 and 4 are controlled over circuits 93, 92 and 94 and correspond with relays IIIK, I2K and I4K of the patent, but the control ofY these circuits has been modified as shown herein so as to include an indication of the condition Yof the approach locking stick relays ZRAS and 4LAS associated with the head block signals, as explained hereinafter.

The signaling system shown herein employs a two-wire reversible line circuit extending between the head block signal locations at opposite ends of the single trackV stretch, which is sectionalized at each intermediate signal location, each section being controlled over front contacts of the track relays for the corresponding block section. The reversible line circuit corresponds generally to that shown in Letters Patent of the United States No. 2,112,945, granted April 5, 1938, to L. B. Yarbrough, for Railway traffic controlling apparatus, but'diifers in that the electroresponsive devices governed over the line circuit to control the signals are here shown as polarized line relays HR., in place of the equivalent signal mechanisms oi' the patent. Furthermore, the contacts of the codecontrolled stick relays in the line circuit of this patent which control the direction in which it is to be energized have been replaced herein by contacts of directional relays'RZDR and L4DR. These relays are controlled by the corresponding code controlled relays ZRHS and 4LHS in a novel manner, in accordance with a feature of my invention, so that as soon as the establishment of either tralc direction is completed by the energization of the line relay at one end or the other, the code-controlled relay at the entrance end is free to be operated as required to control the adjacent signal without interrupting the continuity of theline circuit, andl the. established traic direction` is maintained by lkeeping the relays ZRHP and 4LHP govern the energization of the signal relays H, such for example, as the relay ZRAH for signal 2RA. The code Vcontrolled stick relay ZUS or AUS is energized along with the associated relay 2RHS For 4LHS if the operator closes the key 2U or 4U, Fig. 2, and when energized selects the A signal for a movement from the mainV track MT, and when vdeenergized selects the B signal fora movementfrom .the siding PS, the selection in each case being effective only when the associated track switch occupies the corresponding normal or reverse position.

Each intermediate signal is provided with a line relay HR, a slow acting repeater relay HP, and also with the usual directional stickrelay S for at times supplying current of reverse polarity to the line relay for the next signal in the rear in accordance with the usual practice.

The signals as shownj are to be understood to be of the three position color light type having green, yellow andred lamps forindicating proceed, caution and stop, respectively. To simplify the drawings the ,signal lamps have been omitted and only the wires leadingY theretohave heen shown herein, these bearing the characters G,Y

and R to identify the green., yellow and red lamps, respectively, which are energized over these Wires. Each intermediate signal is also provided witha marker lamp, the circuit `for which hears the reference character M. The intermediate signals are lighted only upon the approach of a train,'the lamp circuits including a loackV contact of the track relay for the section in approach VVto the signal in each case.n l l The line circuit sections are controlled in tandem, energy being applied at the exit end of the block by picking up the corresponding directional relay 2RDR or 4LDR.. Each Adirectional relay is energized overa circuit including back contacts of the line repeater relay HP and of the code contro-lied relay HS at the lsameendof the hlockA the circuit also including a back ccntact of a directional stick relay FSwhich is picked up by an auxiliary line relay FR whenga train enters the block for a purpose hereinafter. to be explained.v As shown, the line circuits are in the conditionV which they assume when the block is vacated afterv a train movement from left to right through the block.

Tracing the circuits in detail, it will be seen that relay llLDR, Fig. 1C,':is energized over a circuit irom terminal B, back contacts l5, I? and I8 of relays d LHS, #LFS and dLHP. relay MBR to terminal C. Signals ALA and 41.03 are at stop, and the approach locking stick relay ALAS asson ciated therewith is held energized over a stick circuit extending from terminal B over hack contact I9 or 20 of relay ALI-IP of.' tLHS, hack. contacts 2I and 22 oi relays SLAHV and 5LB-H, iront contact 23 and winding of relay dLAS to terminal C.

Assuming the leaving signal RA to be at stop, its control relay RAH is released and the pola-rf ized line relay MHR is energized in the reverse direction over the circuit extending from terminais B and C at the pole changer contacts and 25 of .relay 4RAH over front contacts .of relaysIILAS, dLDR, STR, ISTR and MTR, backcontacts of relays I3H1P and I3S and the Winding of relay VH11-IR. Relay MHP isenergized over contact 26 of relay IIIHRL` The line relay I2HR for the next section is energized in the normal direction over the circuit extending from terminals B and C at front contacts 28 and 29 of relay MHP Aover front contacts `of relays I STR and I2TR, back contacts of relays IIHP and I IS and the winding of relay 12HR.'` Relay IZHP is'energized over contact 30 of relay IZHR. The'line relay ZRHR is energized in the normal direction over the circuit extending from terminals B and C at front contacts 3| and 32 of relay IZHP, lfront contacts of relays IITR, ISTR and I TR and back contacts of relay ZRDR andthe winding of relay ZRHR. Relay ZRHP is energized over contact 33 of relay 2RI-1R. The circuit for relay ZRDR, which is similar to that for relay 4LDR already traced, is held open at back contact 34 of relayV ZRHP.

It will be seen that since the signal relay ZRAH is deenergized,.signal 2RA normally indicates stop, and that the remaining head block signals ZRB, ALA andALB also indicate stopfor similar reasons. The intermediate signals are dark, but withthe directional relay 4LDR picked up, signal I2 is conditioned to indicate clear upon the approach of a train, while signal I 4 is similarly conditioned to indicate caution or clear dependent upon the position of relay 4RAH, and the opposing signals II and I3 are conditionedv to indicate stop. l

Although the signals require only three position control, the line circuits shown herein are arranged in a novel manner to provide four distinctive conditions at the head block locations, the fourth condition indicating that the entire single track block is unoccupied. This is effected by coding? or periodically varying the line current in the line circuits which extend from Athe entrance end to the second signal from the exit end of the block for the direction established, that is, for the circuit extending from the location of signal ZRAto that of signal I2, as shown.

Relay I2HR for thesecond signal from the end has been picked up by a train occupying section I3T or I4T, consequently the block indication requires a different condition of the line circuits for the remainder of the block. A circuit is closed over theneutral contact 3i) andnormal polar contact 35' of relay I2HR to energize a code transmitterrelay IZCT, which relay when energized operates its contacts repeatedly at a fixed rate such4 as 75 times 'per minute. Relay I BCT may be, for example, of the type shown in Letters Patent of the United States No. 1,858,876, granted May 17, 1932, to P. N. Bossart, for Coding apparatus. VWhen relay IZCT is in operation its Contact 36 periodically shunts the resistor 3'.'

and thereby periodically varies the current in the line circuits for the remainder of the block,

-thatis, for the portion of the block which ex-M tends from its entrance end to the location of tion, as shown, comprises the circuit for relay 2RH'R, but without interfering with the steady energization of that relay. These variations, however, are impressed upon the primary of a transformer 38 in series with relay ZRHR to cause impulses of alternately opposite polarity to be delivered to a polar stick relay 2RPS connected to the secondary of transformer 38, thereby causing relay ZRPS to operate its contact 38 at the same rate as that of contact 3S of relay |2CT. Each time contact 39 moves to the right a circuit is completed vto terminal B over iront contact 4!) of relay 2R13? to energize a slow release relay 2RX, and each time contact 39 moves to the left, with relay ZRX picked up, a circuit is completed to pick up a second slow release relay ZRY. Relay ZRY is arranged to remain picked up steadily in response to the code operation cf relay ZRPS, and therefore constitutes a block relay which is energized only when the entire block from signal 2RA to signal 4LA is unoccupied. A front contact of relay ZRY controls the energization of wire 89 of the station unit governing the stick indication relay ZRBK at the office. Whenrelay ZRY becomes energized a C. T. C. code is transmitted whereby relay ZRBK is picked up, extinguishing the block indication lamp 2--4BE, and when relay ZRY releases a second C. T. C. code is transmitted to eflect the lighting of lamp 2-4BE provided a relay 4LBK which is similarly controlled by the corresponding block relay 4LY for the opposite direction is also released.

When line conditions permit, the block indication may be superimposed upon the line circuits in a somewhat more simple manner, as indicated in Fig. 3. In this view a marginal relay 2 RM is inserted in the line circuit in place oi transformer 38, relay 2RM being arranged to pick up on a current value higher by a predetermined amount than that supplied through resistor 31, while relay ZRHR picks up on a lower value than that supplied through resistor 31. Relay 2RM picks up only when the 'neutral and left-hand polar contacts of relay IZHR are closed, i

and it therefore may replace relay ZRY in Fig. 1A for controlling the energlzation of wire 89 governing the block indicator.

It is also to be understood that the number oi intermediate signals may be more or less than be relayed from section to sectionin an obvious manner, and in the latter the energization of wire 89 may be controlled directly by the polar neutral con-tacts of the head block signal line relay.

It will be readily apparent from a cursory examination oi the drawings that the circuits shown herein are fully symmetrical with respect to the two directions of trailic movement through the single track block, and it follows that a description of any of the circuits for one direction is equally applicable, by making suitable changes in the designations of the relays and signals involved, to the corresponding circuits for the opposite direction. Thus for example, if the last train movement through the block had been from right to left, relay 2RDR would have been picked up and relay 4LDR would have been released, the line relays IIHR, |3HR and 4LHR and their repeater relays HP would be energized and relays |4HR, IZHR and ZRHR together with the relays HRassociated'therewfli-.h would be released. The code transmitter relay HCT would operate in place'oi relay |2CT, causing the energizetion of relays 4LPS, 4LX and 4LY at station No. 4 in place of the corresponding relays at station No. 2, and relay 4LBK would be picked up to maintain lamp 2-4BE dark in place of relay 2RBK.

l'. shall now assume that the apparatus is in the condition shown in the drawings and that with the object of arranging for a train movement from left to right, the operator moves levers 2 and 4 tothe right and closes keys 2U and 4U, and then initiates the transmission of control codes to stations Nos. 2 and 4. It is to be understood that the code received at station No. 4 will cause the energization of relays 4RHS and 4US as described in the Lewis patent, and that as a result thereof relay 4RAH will become energized to clear signal 4RA, and that contacts 24 and 25 of relay 4RAH will then supply current of normal polarity to relay |4HR to condition signal I4 to indicate clear.

At the oilice, indication stick relay ZRBK is picked up, indicating that the block is unoccupied, and if the indication stick relay 4RHK or INK is picked up, indicating that signals 4LA and 4Ll3 are at stop, the closing of the righthand contact 4| of lever 2 completes a circuit through the upper winding of the polar stick relay 2-4LP, causing that relay to operate its contact 42 to the left to prepare a circuit completed over another right-hand contact of lever 2 and a contactvoi the selector relay 2S during the transmission oi' the code to energize wire |04, wire |05 being also energized over the closed contact of key 2U. The energization of these wires as described in the Lewis patent causes wires 85 and 81 to be energized by the code received at station No. 2, to pick up relays 2RHS and 2US.

` Relay ZRHS, by opening its back Contact 43, opens the stick circuit for the approach locking stick relay 2RAS (similar to that for relay 4LAS already described) so that relay ZRAS releases and by opening its contact 44 releases the locking relay ILR, thereby completing the circuit for the signal relay ZRAH extending from terminal B over front contacts 43 and 45 of relays 2RHS and 2RHP, back contacts 46 and 41 of relays ZRAS and ILR, front contact 48 of relay 2US, contact N closed by the track switch ISW in its normal position, relay ZRAH to terminal C. Relay 2R.AH picks up; and the closing of its front contact 49 in the lighting circuit for the signal ZRA causes the signal indication to change from stop to proceed. The closing of front contact 50 of relay ZRAH energizes wire 94Y thereby causing the C. T. C. station unit to transmit an indication code to pick up relay ZRHK and to release relay ZNK at the oflce, thereby lighting the lamp ZRHE associated with lever 2 (corresponding to lamp |2E oi' the Lewis patent) and opening contact 14 in the circuit for the lower winding of relay 2-4LP, thereby preventing the energization of that winding and consequently contact 42 is held in its left-hand position. Wire |02 leading to storage unit No. 4 therefore cannot be energized in response to a code transmitted to station No. 4 with lever 4 in its left-hand position and consequently relay 4LHS cannot be picked up Iby code as long as contact 42 remains in its left-hand-position. l

Vlt will be seen that the clearing of the signal is dependent upon the release of the locking relays ZRAS and ILS, but before describing the function of these relays Ivshall 'first briefly trace .the movement of a train through the block from l left to right. y

When the train enters section IT, relay ITR and its slow acting repeater relay ITZ release successively, interrupting the stick circuit for re-- lay ZRHS over Wire 86, so that relay ZRHS releases. The opening oficontact I of relay ZRHS causes relay 2US- to release. The opening of Vfront contact 43 of relay ZRHS Vreleases relay A 2RAH, restoring signal 2RA to stop, and the closing of back contact Il3completes a pick-up circuit forV relay ZRAS extending fromterminal B over back contacts 43, 52, 53 and 54 of relays4 ZRHS, ZRAH, ZRBH and ITRl `through relayA ZRAS to terminal C.` Relay ZRAS picks up and completes its stick circuit and by closing cont-act Y causes relay ILR to pick up. Y

The dropping of the contacts of relay ITR in theline4 circuit causes relays ZRHR and rZRHP tosrelease, and stops the periodic operation of relay ZRPS so that relays- 2RX and ZRYv release. The auxiliary line relay ZRFR picks up over the back contacts of relay ITR, its contact 55 completing the pick-up circuit for `the directional stick relayiZRFS, which picks up.Relay ZRFS completes its stick circuit extending t0 terminalv B at backcontact 40 of relay ZRHP., and opensV its contact 56 in the circuit vof relay ZRDR. to hold that circuit open until relay ZRHR is again energized.

When relay ITZ releases,fwirer9l visenergized fto initiate an' ,OScode 'to release relay ITK to light lampITE at the oilice. Since relays 2RY and ITR are released, Wire 89 is deenergized so that this code releases relayrZRBK to complete the circuit for energizing the block indicator'lamp 2-llBlil. Relay-IILP is held deenergized in its last operated or'lleft-hand position until the block is lagain vacated because contacts 51 and 58 of relays ZRBK'and IILBK are bothopen. Wire Y 94 is` deenergized and Wire VSi!) energized by-the dropping of contact of relay ZRAH, so that the code causesy the release of relay ZRHK and the venergization of relay-2NK, consequently lamp 2NE Abecomes lighted and lamp 2RHE extinguished. When the train .vacates section IT, a code will be transmittedto extinguish lampV ITE, and when the train enters section I IT,'relayV I ITR releases to open the lineA circuit, releasing relay.

ZRFRVand back Contact 59 of Yrelay IITR completes the circuits G and M for signal IZ-Which accordingly becomes lighted to display a prov 2-4BE.

nal I 2 tov indicate caution, relay IZVHP energizingrelay ZRAH in the normal direction to condition signal 2BA to indicate clear and also vreleasing relay I2S.

It is to be understood that relay IIRAI-l will -release When'the train enters section 3T and that at the same time an OS code will transmitted fromrstation N o 4 to light lamp STE. vWhen the train vacates sectionv 3T,fsignal I4 will be conditioned to indicate` caution and signal I2 to indicate clean'and a code will be transmitted from station No. 4 to extinguish lamp STE, and at this time the transmitter IZCT is set `into op- 'eration to effect the reenergization of relay 2RY 15 so that a code will be transmitted -from station No. 2 to piek up relay ZRBK,'extinguishinglamp rlhis completes the restoration of the apparatus to its normal condition following the movement of a train through the block from left to right,` as shown. f

Ishall lnext assume thatfthe apparatus has been restored to the condition shown in the drawings and the operator, as before, moves levers 2 and 4 to the rightand initiates ythe transmissionof control codes, but in this case without closing key 2U, in order to permit a train occu- -pying the siding PS to pass signal 2R13, and it willbe also assumed that the track switch ISW Ahas been reversed .bythe train crew.- In this casethe closing of front contact 43 of relay ZRHS will complete a circuit from terminal B over` back contact. of'relay 2US. andcontact R controlled by. switch ISW through relay ZRBH to terminal Cj relayy ZRBH becomingenergized to clear signal 2RB in placey of signal ZRA, the

operations in other respects being .similar to those already described. 4 l

In either case, it willbe noted, the clearing of the signal depends uponthe closing of backcouta-cts ,46 and dlfof relays ZRAS and` ILR, and if the signal is then put to stop manually the time locking islmade eilective to prevent a change of route until-after thelapsegof a predetermined time interval, as I shall now describe. Assuming that the train does not enter section IT but that the signal, is put to stop due tothe -release of relay ZRHS by vthe operator, a circuit will be ceed indication as indicated conventionally by the representation of the signal on the trackplan.

. When the train enters section IZTR releases, and its back contact 6l] completes the pick-up circuit for the directional stick relay -!2S, which picks up, completing its stick circuit extending to terminal Brat back contact 6I v0f relay IZHP. yWhen the train vacates section I IT, current of reverse polarity is supplied to the line circuit over back contacts SI and V32 of relay.

IZHP and front contacts 62 and 63 of relay I2S,

lso' that relays ZRHR and 2RHP pick up, conditicning signal 2BAk to display a caution indica- IET, ,relay rcompleted from 4terminal B over back vcontacts '43,. 52,` 53 and- 64 yof `relays ZRHS, ZRAH, ZRBH and 2RAS, front contactt of relay I TRthrough vrelay ITER to Aterminal C.V Relay ITER is to be understood to be a'vtime element relay requiring energization for a predetermined time interval of the'vorder of from one to four minutesto close its front contactf, after which relay 2RAS picks up,freleasing relay ITER to close its back contact y(il, vVifhereullvorli relayI ILR picks up. It will be seen that the line circuit Vfor governingtralc kmovementsfrom right to leitvwhich extends to terminals B and C at front contacts 68 and 69 of relay ZRASV is held open, thereby preventing `the reversal of the direction of energizationA of f the line circuit with the object ofclearing signal mentioned Contacts 68 and 69 of relay ZRAS lLAior LB until relay yZRAHS is picked up at the end of the predetermined time interval above and `Avthe similar ycontacts of relay 4LAS inthe line circuits' for the opposite direction thus pro- `vide time locking of the :opposing head'block signals 'Y It will also be seen that the pick-up circuits forrelays 2RI`IS and 2US includev frontcontacts 1o and 1|` of relay ILR and that the stick circuit for relay-ZUS is controlled over contact 5I of `relay 2RHS. Consequently after relays ZRHS fil sent rst to initiate the time release of the lccking, and it will be seen that relay ZRHS can be picked up by a code involving a change inthe position of relay ZUS Vonly after the completion of the predetermined time interval.

A distinctive indication by the operation of the time locking apparatus is obtained by extinguishing the signal indication lamp for the duration of the time interval, and this is accomplished in the following manner: Contacts T2 and 13 of relays ILR and ZRHS, in multiple, are interposed in the signal indication circuits by which wires 90, 92 and S4 are energized, and cause the deenergization of all of these Wires from the time relay ZRHS is released to begin the locking period until it is completed by the energization of relay ILR. A connection from Vterminal B to wire 21 of the station coding unit provides a starting circuit which functions to initiate an indication code following each control code, as explained in the Lewis'patent. It will be seen that following the control code which releases relay ZRHS, an indication code will be initiated which will release relay ZRHK Without energizing relay 2NK, so that all 'of the signal indication lamps associated with lever 2 become dark. At the end of the predetermined time interval, wire 92) becomes energized by the closing of contact 'I2 of relay ILR, causing the initiation of a second indication code which will pick up relay 2NK, thereby closing contact 'I4 and also lighting lamp 2NE which informs the operator that the directional relay 2-'-4LP is again responsive to a movement of lever'4 to the left so that he may transmit a control code to pick up relay 4LHS.

It is to be noted that the time locking as above described is initiated Vby dropping contact 43 of relay'ZRHS. The circuits are arranged, however, so 'as to avoid releasing the locking relays as a' result of the energizatio'n of a code controlled relay 'whnthe associated line relay is not energized, as in vthat 'case the signal controlled thereby remainsfat stopand there is no occasion for imposing the time delay. It will be seen that if the line relay ZRHP is in its 'released position when relay ZRHS is picked up so that the signal 2BA or IZRB is prevented from clearing (iront contact 15pol relay rZRHP being open), relayl.

ZRAS is prevented from releasing, being maintained energiied until relay ZRHS is again released, over front contact 43 of relay ZRHS and back yContact 45 of relay ZRHP, for the purpose stated.v

y I shall now assume that with signal 2BA at clear, the operator finds it necessary toV reverse the direction of traiic'and to Aclear signal 4111A.

He will first send a code toA station No. 2 to release relay ZRHS thereby'p'utting signal ZRA to stop. Relay ITER is operated, and relays ZRAS and ILR become energized at the end of the predetermined timeinterval, causir'ig the transmission of `an indication code to pick up relay 2NK,'whic`h is indicatedY by the lighting ot lamp ZNE, andrendering the 'directional relay l2--4LP responsive to the Aoperationuof'lever '4. The operator will then send ajcode tostationNofl withlever 4 in its lefthand position, operatingr contact 42' of relay 2-'4LP to the right and energizing relay 4LHS.

The opening of contact I6 of relay #LHS releases relay 4LDR, and consequently all the HR and HP relays governing traffic movements rfrom left to right release, and when relay IRHP releases, its contact 34 completes the circuit for relay ZRDR. Relays ZRDR, IIHR, III-IP, ISHR, IBHP, v4LHR and 4LHP then pick up in order. Relay 4LHP releases relays ILAS and 3ER; and if switch 88W is normal relay 4LAH picks up toclear signal 4L,

Athese changes being l,registered on the control required direction priori togthe transmission of the code for clearing the signals. It follows that the signals which have been cleared cannot be interfered with by an inadvertent Vattempt to Clear an oppo'singsignal.

'It will now be 'assumed that the 'appariatusls in the.. condition shown but that 'the operator' is. for

some reason unable to clear signal IRA or 2m, even though the stretch. is unoccupied. He may then giveV permission t'o a train 'i'novingfrom left to right to pass the signal at stop and 'enter the blockv under the usuaLn'agging protection. As

, soon as the train enters section IT the. apparatus assumes thev sameconditionA as if the Signal-.had beenA passedat clear, signal- It displayingy Yits clear indication assocn as the train enters section. I:I'-T. It follows that. 'as asthe tzrainp'asses signal I2 itl may continue ythrough vthe block linder'sign'al protection ashereinbeforeldescribed.

t will nextbe assumed that the trame direction is set upfor.. aV movement fromleftoright as shown, and they Operator gives permissinzto a tia'n.;movin`g from. right toleft to .passthrough Athe-block but with Slgfnalfy 1-A or. VS-tl. Whenthe, train Yenters.-'Sectton 3T, thedroppmg of therrtrack relay 3'5IR1will'intiate Vthe rel'eas'effof the energized. relays. HR fandvllPY 'fori governing trainm'ovements fromfleft Theflaist of these relays `to. r leasei-s relay. 2BR?, andthe closingtof itsA backy contact. 34f`energizes the tdinectional v relay which picks Vup to 'cause -eneigizatien of relays im andfHPahead of: the train for governing? traffic moving .frm right" to vleftL relays lxFR and AlLiFSV being also'enorglized.

Since the operation-of :all thcs'erelays lc'ons'un'es some time, it maybe that if the train comprises asingle vehicleitmaiy entirely 'out off section 3T-before currentsis available to .pickuprelay IILFR. To insure the energizationof relay `ILFS 'undenthis-'condition relay `ItLFR. is `airgardless of whethervthe associat'edhead-block signal has been cleared -or not, andalthougn'the system of v my ti'r'u'fentic'in ein'ploys-VA onlyy rtwo ine wires, itprovides a degree of flexibility in opor- :atlio'n' under abnormal cnditio'nsas well asunder normal conditions heretofore attainedA onlydn systems employingindependent"normally enerv gizedline circuits for the twddirections.

Although Ighave herein shown and described only one form of vrailway traino controlling apparatus embodying my invention, andf'one modifloat-ion of a feature thereof, it is understood that various changes and lmodifications may be made therein Within therscopeV of they appended claimsy without departing `from the spirit and scope of my invention.l i 1 Having thus described my invention, what I clairnis: j v ,i Y

1. In a signaling system for railroads, a stretch of single track provided with head block signals located at each'end and intermediate signals at spaced locations Within said stretch, for governing -traflic movements in opposite directions through said stretch, va reversible line system extending between thehead block signal locations comprising a `pair of line wires sectionalized at each intermediate signal location, a line relay for eachsignal, a sloW acting repeatingjrelay t theirepeating relay for the associated head block for controlling each signal controlled by a front lcontact of the associated line relay, a directional -reiay at each end offthe stretch, an energizing circuit for each directional relay including a back 4contactof the repeating relay'for they signal at the same end of the stretch and also including a "manually f controlled --contact, means for alternatively connecting the Winding of each head Y'lolock signal line relay or a source` ofl current to the line wires at the corresponding end of theV stretch comprising back and front contacts, re-

spectively, ofn the vassociated directional relay, Vand means for alternatively connecting the winding oi each intermediatesignal line relay vorA a source oi current tothe line'vvires extending in advance of the correspondingY signal, comprising l'back and vfront c'or'itactsrespectively,` of the repeating relay for the opposing signal at the .same location. Y 4

2.1n a signaling system for railroads, a stretch `of'single track, divided into tracksections,` each providedvwith` a 'track circuit' including a'track relay, head block'signalslocated at each end and intermediate 'signalslocated at the ends oftrack ,sections within jsaid stretch, for ,governing vtraviic `movements `in .opposite directions* through said stretch, a reversible line circuit 'systemextending between the head block signal'locationsrbut "divided into sectionsk each line vcircuit section extending" frem onetsignai to. the next and including front contacts of the track relays for the Xintervening track sections, a linerelay for Veach signal, afslovv acting repeatingrelay for controlling each signal controlled by a front contact of the associated line relay, adirerctional relay at eaoh'end of the stretch, an energizing circuit for l each directional relay fincluding a back contact of the repeating relayfor the signal at the same end of the stretch, and also including a manually ycontrolled Contact, meansffror alternatively connecting -thevvvinding of cach headnblock signal `line relay or a source of current to the line cir,-V

Vor a source oi current to the line circuit `section extending in advance of the corresponding signal, comprisingback and front contacts, respectively, of theV repeating relay; forthe opposing signal atthe same location.

3. In a signaling system for railroads, a stretch of single track Ydivided into `track sections, each provided with a track circuit including a track relay,*head Iblock signals-locatedat each end and intermediate signals located attheends of track sections Within said stretch, forgoverning traiiic movements in opposite directions through said stretch, a reversible line circuit system extending between the head, block signal locations but divided into sections each extending from one signal to .the next and including front contacts of the track relays for the intervening track `sections, a line relay for each signal, a slow acting repeating relay for controlling each signal controlled by a Afront contact of the associated line relay, a stick relay and a directional reiay at each end of the stretch, a pick-up circuit for each stick relay closed when a train enters the stretch at the corresponding end provided the line circuit section directly in advance of the train is energized aty its distant end, a stick circuit for each stick relay controiled by a back contact of signal, anenergizing circuit for each directional relay including back contacts of the associated repeating relay and stick relay and also including amanually controlled contact, means for alternativelyconnecting the winding of each head block signal'line relay or a source of current to the line' circuit section terminating at the corresponding end 'of the stretch comprising hack and front contacts, respectively, of the associated `directional relay, and means for alternately connecting the winding of each intermediate signal line relay or a sourceofcurrent to the line circuit section extending in advance of the corresponding signal, comprising back and front contacts, respectively, of the repeating relayfor the opposing signal at vthe same location.

4. In a signaling system for railroads, a stretch of single track -divided into track sections each provided with a track circuit including a track relay, head block signals located at each end of the stretch for governing traffic movements in opposite'directions into said stretch, a reversible line circuit system extending between the lhead block signal Vlocations including frontl contacts controlled by said track relays,- a line relay for controlling veach signal, a directional relay and a manually controlled contact at, each end of the stretch, means for alternatively connecting the Winding of each line relay or a source of current to the line circuit system at the corresponding end of the stretch, comprising back and front contacts, respectively, ofthe associated directional relay, and an 'energizing circuit for each directionalY relay includingV said manually controlled contact and a contact which closes in response to the release of the associated line relay, and also including av contact which opens When a train 'enters the stretch andthe line circuit system is energized at its distant end, even though the lineV relay at the end at Which said train enters has not been picked up.

5. In a signaling system for railroads, a stretch of'single track divided into track sections each provided With a track circuit including a track relay, head-block signalslocated at each end of the stretch for governing traiiic movements inl controlled by said track relays, a line relay for controlling eachI head V:block signal, a manually controllable directional relay at eachY end of the 8 2pac-,ns1

stretch, means for alternatively connecting the winding of each line relay to the line `circuit system 0r for energizing said line circuit system at lthe corresponding end, comprising back .and front contacts, respectively, of the associated directional relay, and means controlled by each line relay when energized for .preventing the. enf ergization of the associated directional relay.

6. In a signaling system for railroads, astreteh of single track divided into track sections each provided with a track circuit including a track relay, head block signals located ,at leach end of 'the stretch for governing .traffic movements .in opposite directions into said stretch, a reversible rline circuit system extending between the head block signal locations including iront contacts .controlled by said track relays, a Vline relay for controlling each signal, a manually Acontrollable directional relay at each end of .the stretch, ,means for alternatively connecting the winding of Veach line relay .to the linecircuit systemor .for energizing said line systemat the corresponding end, comprising back and front contacts, respec+ .tively of .the associated directional relay, `means .controlled by each line relay Vwhen energized .for J preventing the energization of l,the associated .di- Arectional relay, and other means -effectivewwhen a train enters Ythe stretch and releases the line .relay at the endat lwhich the train enterstoprvent the energization yoi the associated directional relay until that line relay -is vagain ener- .gized.

7. In an absolute permissive block signal system, a stretch of railway trackdivided intoblock sections provided with continuous track `circuits Vincluding-track relays, aline'circuit systemcom- ,prising a pair of linewires extending 'from (the entrance to the exit end of said vstretcharidfdivided into sections corresponding 4to said block sections each section of saidlinecircuit system including front contacts controlled by the intervening track relays, a three position lsignal vat :the

entranceto each block section forgoverningthe movement; of traic in a given,directionneleci .troresponsive device forfcontrolling eachsignal i,

adapted to be'energizedjover the linecircuit sec- .tion directly in advance thereof, vmeans 'forsuplplying current of `normal or reverse polaliliyzto the line circuit section terminatingat tbe-exit .endocf the stretch, ,means atseach intermediate v signal location forsupplying current of normal .relative polarity to the line circuit sectionelitend- .ing to the rear thereof'only-,When'the electrore- Asponsive-v device at-that location is energized, and Aforsupplyingcurrent of reverse relativepoiarity all of said track-relay controlled contacts are closed forV energizing said block relay, a block i81- dication relay at said ofliceremotely controlled by said block relay, amd-meanseffective 1when any portion of said stretch isfoccupicd asmanitested by the condition oisaid block indication relay for preventing the .-disoonneotion--of'fsaid source of current V'from the line. circuit system in response to theoperationfof .said .manually operable means. I f j 8. .In a. signaling system .for a `stretch .of railway track provided with continuous trackcirf cuits 'controlling -a sectionalized line .circuit and with signals at the entrances to block sectionsdefined by said Atrackcircuits for Vgoverning trafc movements in a given direction .through .said stretch, :in which 'each Signal indicates .caution or. clear dependent upon `the normal .or reverse enorg'iaatiom respectively, .of a polar line relay included in a line circuit .section Awhich is closed only when `the 1block Vsection directly ,-inY vadvance of such signal is unoccupied, each signal indicating stop when its line relay :is Adeenergiited, and :in which thefenergized ordeeneraized condition Yof each .line relay for intermediate signal in said .stretch ,controls .the normal .for reverse .energization .respectively of .the Alinie ,circuit section ,for the 'next block section in ,the rear thereof, the combination v.of .a block relay yat 4the Ventrance .to saidstretoh, with :means iai superimposinga distinctive indication :uponon'e or more sections of lsaid line circuit :t0 ienergie said block ,relay only when all .the .block seotionsiare unoccupied, irrespective of .the numberlafsaid Sections. and a '.visualindicator controlled bysad block relay.

.9. Ina vsignaling system ziaria stretcher Vrail,- ytav track provided with centmuus Ytrad; Gircuits A,controlling a -sectioneliesi line `circuit and with .signals at kthe entrances to -block sections ,defined yby said V.track .circuits f orovernirie .trarfcfmovements in ,a 1 given .direction through said stretch, in which .each signal .indicates Vcaution er Clear dependent upon :the normal v0r reverse enersizetien, .,Iespectively, .of a Polar line .relay .included ,in aline circuit section-.which vis closed only when the block-.Section ,directly in .advance of such signal is unoccupied, each signal vindicating Ystop Whenits Vline,relayisdeenergiaed and ,in-which the-energiaed or deenergiaed condition .Qf,each line .relay `for an intermediate Signal vin said stretch controls the normal or greverse energization vrespectively 4of ,the vline .circuit .section forthenextblocksection inthe rear thereof, the combination Vvofla block relayoat the entrance to said stretchw`ith means/dependent upon'thenormal energization of the linesrelay .for .thes'econd ,signal Vfrcmthe exit end of .saidstretch `for increasing .the current .suppliedto the line circuit `portion in .thelrearv of that signalbya predetermined amount', irrespective ofthe number of sec tions in sa'id portion, means latthe entrance cto Ythe vstretch controlled over said lastnarned lle circuit prirtionand selectively responsive to Said increasedcurrentfor energizing saiiibloek relay, 'and a Vvisualindicator controlled'by said block relay for indicating when av trafinfis occupying anyportion of 'saidstretcn A 10.In a signaling -systemvfor a, stretch of railway Ytrack provided with Vcontinuous'track circuits controllingv a sectionalized line circuit and with signals-abuis entrances-to mock sections dened Ybyl said*l track circuits forv governing traf/- fic movements in a given direction through 'said stretch, vin Avs'fhicii each signal indicates ycaution or 'Y clear Kdependent upon themennal orf-reverse energizatiom respectively, ofafpolar line relay ineldedinr-a line circuit sectiony which is--closed only when the blockl section diectlrylin advance 'of -.'suchsignal is unoccupied, each signal indicating stop .yirhen-r its line relay is gdeene'rgized, andin :which the. energized or. deenergized .con- 'ditiQn-oi'eoclrline relayfonanimmcdiete. Signal in Asaid kstretch controls the V10F-H9131 101' "IeVHSe enereization rcspectiYelY. 9i line circuit section for the next blocksoction inthe rear thereof, the combination ofja block relay 'at-the entrance to`sai`d stretch, with means dependent upon thenormal energization ofthe, line relay for' the 'second-signal vvfrom, the exit; endY of said stretch for -periodically varying the current supplied to the line circuit portion in the `rear of f that signal irrespective of the number of sections in suchportion and vwithout operatively affecting said line circuit when energized at either' end for energizing the block relay at the other end whereby one block relay or the other is energized when all the block sectionsare unoccupied, irrespective of the number cf said sections, and means controlled by said block relays for preventing the deenergization of said line circuit in response to the line relay in any section, meansy at the en- 4 trance to the stretchV selectively responsive to` lthe periodic variations intcurrentA in said last named line circuitfportionv for energizing said block relayyand a visual indicator controlled by said block relay forindicating when' a train4 is 'occupying any'portion'of said stretch.

polar line relay included in aline circuit section" which is closed only when the block section di-f vvrectly in advance of such signal is unoccupied,

each signal indicating stop when its line relay is deenergized, and in which' the energized or deenergized condition of each line relay for an inter-"1f mediate signalv in said stretch controls thenofr- :mal or reverse energization respectively of the line circuit section for the next block section in the rear thereof; manually controllable vmeans at a control oiiice for energizing said line circuiti'V at one end of the stretch or the other for estab-Y lishing the direction of traflic movements through said stretch; a block relay at each end of said stretch, means for superimposing a distinctive' indication. upon oneV or more sections of said'line'- the operation of said manually controlled means for reversing the established direction 'offtraic unless one block relay'or the other is. energized.

13. In a signaling system, a stretch fofl railway track having a signal at each end for governing I the movement of traflic into the stretch, a signal control relay for each signal, means controlled by eachV signal control relay when energized for clearing the associated signal in accordance with traffic conditions in said stretchfbutonly if the signal at the' other end of the stretch is at stop and its control relay is deenergized, control means at -a' central oflice comprising a signal lever for each signal, a two position directional relay ofthe polar stick type, signal indication means controlled -by the signals, and block indication means controlledVV by traffic conditions in said stretch, aV circuit for operating said directional relay to one position or the Vother when one signal lever or the other -is reversed, each lio circuit when energize'dat either end for energizl ing the block relay at the other end whereby one block relay or the other is energized when all the block sections are unoccupied, irrespective of the number of said sections, and direction locking means at Vsaid ofce controlled by said blcckrelays for preventing the deenergization of 4said line circuit in response to the operation of `,said manually controllable means When a train is occupyingany portion of said stretch.

l2. In an absolute permissive block system for g a stretch of railway track provided with continnous tra-ckcircuits controlling a sectionalizedv line V .circuit and with signals att-he entrances to block v sectlonsdeiined by said track circuits for governing trahie mevements in opposite directions through said stretch, in which each signal indicates caution or clear dependent upon the nornial ory reverse energization, respectively, of a polar line relay included in a line circuit sectionwhich is closed only when the block section directly in advance of such signal is unoccupied,

Veach signal indicating stop when its line relay is deenerg'ized, and in Whichsthe. energized or deenergized Acondition of each line relay for an intermediate signal in A4said stretch controls the normal cr reverse energization respectively of the line circuit section for the next block section in the rear thereof; manually controllable means at a control cnice for energizingv said line cir-` cuit atene end of the stretch or the other for.

`tinctive indication upon one crgnore sections; of

such circuit being closed only when the' signal indication means indicates that the vopposing signalis at stop and the block indication means indicates that the entire stretch is unoccupied, and a circuit controlled by each signal lever when reversed closed in response tothe operation of the directional relay to said corresponding position for energizingthe associated signal control relay. l

`14. In combination with a stretch of railway track having a signal at each end forgoverning the movement of trafc into the stretch, a manually controllable signal. control relay for each signal, a directional relay of the two position type arrangedto remain in its last operated position when deenergized, a ysignal lever for each signal, control circuits for said signal control relays including contacts controlled by'said directional relay and by said levers, one control circuit-being,closed'ohly when one signal lever is reversed and said directional relayris in one position and the other only when the other'signal lever is reversed and said directional relay isvin its other position, and a secondrcircuit controlled by each lever for operating the directiom pal relay to a. corresponding position to estab- .n signals at spaced points withinv the stretch for governing the movement of traiiic through the stretch in opposite directions, arcontrol relayfor iv each'head block signal, an energizing circuit for each head block signal controlled in accordance with traflic conditions in said stretch and closed only when. the associated'control relay is `4ener- .gized, an energizing circuiti-for' each intermediate vsignal closed when the portion of thev stretch in advance thereof is unoccupied but only if the control relay for-the opposing head block signal `is deeriergized; direction selecting means, .block indicationlmeans, and a signal leverl for each lcontrol relay, Aall located at a control office, circuits controllable by said signal levers when said block indication vmeans is conditioned to indicate that the entire stretch -is unoccupied for actuating said A,direction selecting means to one position or another to 'establish vthe desired direction for traiic `movements through the stretch but 'Without energizing either 'control relay, and a circuit vcontrolled by-each signal lever for selectively energizing the corresponding control relayclosed in response to the actuation 4of saiddirection selecting means to the corresponding position.

16. In a centralized tramo control 'system for railroads, a stretch lof railway track having a signal at each end for governing the movement of traiiic into the stretch, a control relay for each signal, an energizing circuit fior each sig-'nal closed when the associated control relay is energized and the control `relay for thes'ignal at'the other end vof the stretch .is lcenergizett; direction selecting means, block indication means, and a signal lever for each control relay, all located ata control cnice, ycircuits cori'trrzilla'ble fby :said vsignal levers Vvvhensaid block indication `means is conditioned `to. indicate that "the eri-'tire stretch is unoccupied for actuating said 'direction lselecting means to onelposition or lto establish the desired direction for Ytiifc Jmotel'iie'rits `through the stretch but without-'energizing either control relay, and `a circuit controlled 'by each signal lever 'for selectively energizing' the cor-responding control relay closed iin response to the actuation of said direction :selecting 4means y:to the corresponding position. l

17. In Vcombination with a' .hand throw track switch, two signals for governing traino movements in a trailing direction over the two routes established by the vtla'clr `Switch in Vits normal and reverse positions, respectively, a looking relay energized -only when both said signals findicate stop, two manually controllable relays which may be picked up only when said locking -relay is energized, la line 'relay control-led by traine conditions in advance `4of 'sa-id lsignals, means effective when one of marruailycontrollable relays and said'lline rela'yla-re both'energizecl -to release said locking relay, circu'lts *for selectively yclearing one signal or the other closed over contacts of 'said manually controllable ielays according as one or both are picked up, each including a front 'contact of 4said `line relay, a back contact 'of ysaid locking reliay and a contact controlled by the track switch is closed only when 'the Vswitch occupies a Vposition to establish the route governed by the selected signal, and means effective ii' said one manually controllable relay is released to 'thereby restore the cleared signal manually to stop for vdelaying the energization of lsaid locking relay until said signal `has 'been at stop for a predetermined time interval.

18. In combination with a stretch 'of railway track having a signal at each end for governing trailic movements into the stretch, a locking relay for 'each signal energized only when vsuch lsignal indicates stop, -a line relay for each signal having an energizing circuit controlied Aby trafc Vconditions in said stretch and by a front contact of the locking relay for the opposing signal, a manually controllable relay l'orv each signal which may be picked up only when the associated locking relay is energized, means effective when either manually controllable relay and the associated line relay are both 'energiaed for releas- .ing the vassociated locking relay, a circuit ior clearing each-signal including front contacts of `the associated manually controllable relay and line yrelay 4and aback contact of the associated klocking relay, and means eective if vsuch manu- Ially controllable `relay is released to thereby restore the associated signal manuallyto 'stopfor Kdelaying the -energizationot the associated lock- -19.,-In.a signaling system for railroads, a

stretch, a vreversible line circuit fsystem yextending between the head block signal locations comprising -a pair AOnline wiressectlenalized at a plurality of intermediate locations, an eleotrorespondevice yfor controlling each signal, a vdirectional relay at each end of the stretch, en-

ergizing circuit for 'each-directional relayincluding Aa contact controlled "by the yelectr-ofessionlsive device `fer 'the signal 'at the same end vof 'the stretch -in series with la, manually controlled contact, means for alternatively connecting the winding Yof each such electroresponsive ldeviceor 'a source -of current to the line Wires fat the correspondingvend of the stretch comprising back and -end of the stretch in response rto lthe closing 'of the associated manually -controiled `contact 'for extending such energization section by section yte energize the electroresponsive'devioe at the other 'end of ythe stretch, lamd means conti'oiled by each electroresponsive device when energized for g .its contact in the lcircuit `'for 'the directional relay 'at the :same end of the strewn.

ill). In -a 4signaling Vsystmn for railroads, a Astretch 'of `single track divided into track Se'ctions each provided with a track circuit mcluding-a track relay, head block signals 'located 'at each -enfd Iof the Lstretch for governing trailic movements in .opposite directions into 'said stretch, a reversible line circuit system 'extending between the head fblock signal '.locattonsincludlng front contacts controlled by said tm'ck relays, an electroreeponsive Vdevice `for controllingeach signa-l, a directional relay, a, directional stick relay and a manualiy controlled relay 'at each end of thef'stretch, means for alternatively Connecting the'w-inding 'of `each `line relay 'or a source 'of current to the line circuit system at the corresponding end -of the stretch, comprising back and front contacts, respectively, of the associated directional relay, an energizing circuit for each directional relay including ln 'series a back 'Contact of the associated manually controlled relay, a contact vwhich is held open as long as the associated electroresponsve 'device 'is energized, and a back contact "of the associated directlonalrsticl: relay, a pickupcirclt ,for each directional stick rc1-'ay closed when a train 'enters the 'adjacent 'end of the stretch to 'deener'glze the assciat'ed electroresp'on'sive device, and' a stick circuit elfecti'vevto -hoifd such'directlonal relay picked up until the associated electrorespdnslv device is again energized;

21. In a signaling system for railroads, 'a stretch `of single track provided with continuous track circuits provided with track relays and having head block signals located at each end for governing Ytrarlic lin'ownfsen'ts in opposite 'directions into said stretch, an electroresponsive device for controlling each signal, areversible line circuit system controlled by said track relays for controlling the operation of said electroresponsive devices, a directional relay at each end of the stretch, an energizing circuit for each directional relay including two contacts controlled by the electrorespcnsive device for the signal at the same end of the stretch in seriesrwith a manually controlled contact, means comprising front and back track circuit for each block section, each having a trackrelay, head block signals for governing trafiio movements into the stretch in opposite directions, a manually controlled relay adjacent each signal, line circuits divided into sections corresponding to the block sections for controlling said signals, each line circuit section incontacts, respectively, of each directional relay for alternatively connecting a source of current to the line circuit system to energize it at the adjacent end or for rendering the associated electroresponsive device responsive to the energization of the line circuit system eiected by closing the manually closed contact at its distant end, means controlled by each electroresponsive device when energized for opening one contact in` cluding contacts controlled by the track relays which are closed only when the corresponding block section is unoccupied, means comprising back contacts of each manually controlled relay for controlling the line circuit for that signal which governs traic movements into the stretch at its opposite end, means comprising front contacts of each manually controlled relay for controlling that signal which governs traffic movements into the stretch at the adjacent end in accordance with the condition of one or more sections of its line circuit, a block relay at each end of the stretch, means for energizing each block relay over the line circuit for the adjacent signal but only if the track relay controlled contacts in each section o f such line circuit are closed, and means preventing the operation of either manually controlled relay after the other manually controlled relay has been operated unless one block relay or the other is energized. l

, HENRY s. YONG. 

